Energy expenditure in women and men with COPD

Many patients with chronic obstructive pulmonary disease (COPD) lose weight. Successful nutritional intervention is vital, thus assessment of energy requirement is required. The aim of this study was to present an improved possibility to assess energy requirement in patients with COPD.

Pub Med search was conducted for all the studies reporting total energy expenditure (TEE) measured by doubly labeled water (DLW) method in patients with COPD. Four studies were identified, whereof three were conducted in Sweden. The present analysis is based on these three studies of which the data was acquired.

There was a large variation in resting metabolic rate (RMR) and TEE. Body mass index decreased significantly with increase in disease severity (p < .001), and correlated significantly to forced expiratory volume in 1 s (FEV₁) % predicted (r = .627, p < .001). FEV₁% predicted had a significant correlation with RMR/kg body weight (BW)/day (r = -.503, p = .001), RMR/kg fat-free mass (FFM)/day (r = .338, p = .031), and TEE/kg FFM/day (r = .671, p < .001). Compared to men, women had a lower RMR and TEE/kg BW/day (p < .001 respectively p = .002), and higher RMR and TEE/kg FFM/day (p = .080 respectively p = .005). The correlates of: RMR/kg BW were gender and FEV1% predicted; of TEE/kg BW the correlates were age and gender, and of TEE/kg FFM the correlates were age and FEV1% predicted.

In this study, we have presented a possibility to assess energy requirement per kg BW/day and per kg FFM/day in patients with COPD in clinical settings. However, gender, age, and disease severity must be considered.